Video image systems have the capacity to provide traffic data over a wide area. Most other
detector technologies can only provide point measurements of traffic data and can only infer traffic
conditions between these points. With the potential of wide area viewing, linked video sensors are
capable of recording queue lengths, flow profiles, and vehicle decelerations over a number of
traffic lanes. However, environmental effects such as inclement weather, shadows, reflections
from the pavement, and poor lighting can cause missed or false detections. Missed detection of
smaller vehicles trailing larger vehicles is an issue for video image sensors as well.